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Science Frontiers ONLINE No. 124: Jul-Aug 1999 |
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Forest Rings
No! These rings have nothing to do with crop circles, nor with fairy rings either.
Forest rings are best appreciated from a light plane. Hunters and hikers in Canada's boreal forests walk right across the rings without noticing them. But from the air, they are striking apparitions. Most are less than 300 meters in diameter, but the largest is 2 kilometers across. Basically, they are annuli of sparse growth amid dense stands of trees both inside and outside the rings. The barren rings -- some 2,000 have been found -- appear light-colored against the dark green of the healthy forest growth.
Why don't trees grow well within the rings, and why the neat circles?
At first expanding rings of fungus infection were suspected, something perhaps like the fungus that creates those fairy rings on lawns. But no fungus has been found on the tree roots. One curious fact was discovered about the soil where tree growth is sparse. The soil constituting the rings is poorly drained and is depressed 1-2 meters below the surrounding healthy forest. These circular depressions support mainly peat and tamaracks. But what causes these ring-shaped depressions?
One theory holds that the rings are the suface expressions of diamond-bearing kimberlite pipes, like those in South Africa. A few prospectors are already staking diamond-mine claims! Another theory supposes that the rings are created by huge, natural electrical batteries that exist in the carbonate soil. The current flow supposedly creates acidic conditions that eats away at the soil causing it to slump in a circle around one terminal.
(Shilts, ELizabeth, "Stranger Than Science Fiction," Toronto National Post, March 16, 1999. Cr. G. Duplantier via L. Farish.)
Comment. May UFOs are to blame after all!